Introduction
Now, Frogboy requested that we think up some ideas for some tournaments we may like to see in the game. Now, I for one have always been fan of cooperative contests which allow players to not only ally, but cooperate with a team to achieve a common goal. One common goal would be to gather the most land, and at the conclusion of the time period the alliance with the most land wins. That's how it is on the simple end of the spectrum, but now let's get down into the nitty gritty.
The idea is far from new and original, as it has been utilized by many games over the years as far back as Heavy Gear for the PC. One of the latest and perhaps the most popular examples has been infused within an MMOFPS known as Planetside where three names compete for land, endlessly, for seemingly no real reason other than to boast who has the most land. So, in order to avoid copyright infringement, I boggled for several hours on how a similar structure can be applied to Demigod, allowing players to ally themselves with a large force and within that force, cooperate with guilds and groups to achieve a goal.
The idea is very complicated, but it doesn't change the gameplay itself - it merely adds the fabric of an additional metagame that incorporates Favor and applies it to the piece of land that is contested between three factions. I've provided visual aids to help in this explanation, and I've also put together a little story, as well as additional team-play elements that may work very well for cooperate clan/guild efforts. Due to the seer complexity of this, I would not expect it to be included with the release of the title - and should not be seen as a quick-to-implement suggestion. If the community likes the idea, or has critiques, please comment and amend as needed.
War of the Trinity
Since I am unfamiliar with the full story of Demigod, I've decided to try and make a decent subplot that may work very well with the existing game. In this Tournament, reality itself has been torn into three alternate planes of time and space. As the power of the alternate gods began to clash, it was clear that as the universe spun like a great clock - only one reality may be the true, dominant reality. The demigods have been sent to perform the god's dirty work, where they must face against their own counterparts to prove who truly is the strongest version of themselves.
The gods have made it possible to transcend the fabric of space where demigods may cross into other realms. Claiming power and favor with might that further expands their own reality and consumes another.
The Theory of Function
In this great metagame players may join up with one of three factions. Switching to different factions may be possible, but with great penalties. Each faction is measured by players currently online battling and also the amount of land they currently control. Land is not exactly "land" as a representation of the fabric of space itself, and the symbolism for the unfathomable state of transcending the mortal plane. On these higher planes of existence players join up with others of their chosen faction to fight for the greatest sum of land, and at the conclusion of the tournament's term a winning faction is declared.
There are 3 factions, and three primary layers to this overall meta game.

Layer 1: Demigod, the game.
During Beta we've experienced various settings. Such as stronger towers, faster spawning reinforcements, strong reinforcements, higher death penalties. These settings are what I'd like to see woven into this metagames fabric. Based on what segments of "land" in a contested territory are claimed, the game settings for a certain team are altered based on the segments they own in a territory adding an element of strategy.
To Clarify, allow me to submit an example. Assume that the Yellow Faction has claimed territory benefits which increases their tower's strength, increases their exp, and reduces their spawn rates. Much like the element of flags that are already present in the game, just on a larger more metagame scale. This would give them a clear advantage over anyone trying to take over their territory. But other teams can battle for those benefits as well, and can even claim them by taking over the segment of land that provides them with a territory wide benefit.

Owning these segments will effect only the gold team, for all games within the territory.
Layer 2: The Territory Map

This is an rough sketch idea of a territory. Within the territory there are nine segments, each which provide a territory wide benefit to the team which claims them. Between each segments are pathways laid out by the gods, and it is up to the Demigods to fight on these pathways to force to claim another segment for their faction. This is where Favor comes into play. Favor is won normally through game play, but at the end of each game the points are instantly invested into your faction's progress towards capturing a segment.
Let's assume you are battling for a territory with all three factions in place. For instance the area of the map where Purple team's Exp +10% is under threat of both Blue Team and Gold Team. Each pathway has an influence, the influence is the amount of favor invested into that pathway by a faction. When a team reaches a certain number of influence upon a pathway they'll claim the next segment that path connects to.
When a team wins, half of the points will go into increasing their influence while the remaining half goes into reducing the loser's influence. The losers favor will simply go into increasing their own influence. This is how the math would play out after each game (In a system which assumes winning will gain you more favor):
Purple Team Wins 650 favor total in a battle against Gold Team, who won 235 favor in the match.
Winners: 650 Favor Gained
Purple Team's Pathway Influence increases by: 325
Gold Team's Pathway Influence is reduced by: 325
Losers: 235 Favor Gained
Gold Team's Pathway Influence increases by 235
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Purple Team gains 325 favor total.
Gold Team gains 90 favor total.
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325 - 90 = 235
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Overall: Purple Team's Pathway Influence increases by 235 points.
*Note: The Green is considered a neutral segment. In order to claim this players will have to battle against AI Demigods.
Layer 3: The Primary Map

This is the overall progress of the Trinity War. Within this map there are twelve territory maps. Ideally, each territory map will have a unique mixture and arrangement of segments for each team to claim. The color lines lay out the floor plan for the pathways which connect each territory. Once a faction completely owns all the segments in a territory, they'll be able to move on to the next territory it connects to. Alternatively, a faction may just need to be able to control the primary pathways which link territories together. That's a little more difficult to explain, but a creative imagination can see what I'm talking about by the visual examples I provided above.
Global Faction Benefits
Because not every team will be perfectly balanced at all times. A player's faction can gain benefits and bonuses in Experience and Gold based on their overall standings and performance in the war. This is determined by the Primary Map, not the Territory Map. If the overall population of a Faction is low and they are doing poorly and have little land, the more benefits they'll receive - these benefits will stack with Territory Benefits, Flag Benefits, and Favor Item Benefits. If a faction has a vastly high population and is dominating the primary map, they'll receive only benefits from Territories, flags, and items. Yes, this is another feature inspired by Planetside.
Groups, Clans, and Contested Pathways
Now Segments within a Territory are contested when two or more factions fight upon that path. Players can join in the fight upon those pathways by clicking on them, sending them into a waiting room where games are being automatically created. Since this is a tournament, automatching should be in place. But what if you wish to play with your teammates? Familiar to Dawn of War 2; clans, guild mates, and friends should be able to form battle groups prior to entering battle. This will allow clans to fight together and tactically defend regions against other skilled clans who will be battling hard to make their faction number one.
Tournament Time Frame and Conclusion
Each tournament should probably span for the duration of a month. Where at the conclusion of the month the winning faction will be declared and perhaps even rewards and achievements provided to those who took part. Participation should weight heavily on the reward given, where even a losing faction who's best fighters fought long and hard will still get high rewards while others on the winning team who just mooched off everyone else's progress will likely get very poor spoils. Performance = Benefit, win or lose.
Now, I'm fully aware of the vast complexity of this tournament suggestion. If it were to be made possible, it would more than likely be part of a future expansion pack which would be driven to sell this even as a Single Player model. Please feel free to offer comments. I know it's not fully original, but I did a great deal of brain storming to try and translate it to Demigod and how it may be fun to play with clans and groups where the metagame itself becomes one of the primary focuses of the players on top of the normal game it overlaps with.